Watchdog circuit and electronic power device

Abstract

The present application relates to a watchdog circuit and an electronic power device. During actual operation, a voltage divider circuit can input a reference voltage into a first input end of a first comparator; on the basis of the input state of a dog feeder circuit, the dog feeder circuit itself adjusts the charging-discharging state of a charging-discharging circuit with respect to a second input end of the first comparator, so as to change the input voltage of the second input end of the first comparator; and finally, the first comparator performs comparative analysis on the basis of the reference voltage and the input voltage, and feeds back a corresponding level signal, implementing monitoring and restart control of an object to be monitored accessed by an output end of the first comparator.

Description

Watchdog circuits and electronic power equipment

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202311653498.7 filed on December 4, 2023, entitled “Watchdog Circuit and Electronic Power Equipment”, which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application relates to the field of electronic power technology, and in particular to a watchdog circuit and electronic power equipment. Background Art

[0004] With the rapid development of science and technology, control devices such as MCUs (Microcontroller Units), DSPs (Digital Signal Processors), and FPGAs (Field Programmable Gate Arrays) are increasingly used in various control systems and control equipment. During operation, these devices are susceptible to electromagnetic interference and other interference, which can cause program errors or infinite loops. A watchdog function regularly monitors the internal status of the control device and sends a restart signal if an error occurs.

[0005] However, in the related art, the watchdog chip has poor configurability flexibility and is difficult to meet the low-power operation requirements of devices with high power consumption requirements.

[0006] Summary of the Invention

[0007] Based on this, it is necessary to provide a watchdog circuit and electronic power equipment to alleviate the problem of poor configurability of the watchdog chip, so as to meet the low-power operation requirements of devices with higher power consumption requirements.

[0008] The present application provides a watchdog circuit, including a dog feeding circuit and a hysteresis comparison circuit, the hysteresis comparison circuit including a voltage divider circuit, a charge and discharge circuit and a first comparator; the first input end of the first comparator is connected to the output end of the first comparator through the voltage divider circuit, the second input end of the first comparator is connected to the output end of the first comparator through the charge and discharge circuit, and the dog feeding circuit is connected to the charge and discharge circuit.

[0009] The above-mentioned watchdog circuit is constructed by a voltage divider circuit, a charge-discharge circuit and a first comparator to form a hysteresis comparison circuit. The first input terminal of the first comparator is connected to the output terminal of the first comparator through the voltage divider circuit, and the second input terminal of the first comparator is connected to the output terminal of the first comparator through the charge-discharge circuit. The dog feeding circuit is connected to the charge-discharge circuit. During actual operation, a reference voltage can be input to the first input terminal of the first comparator through the voltage division of the voltage divider circuit. The dog feeding circuit adjusts the charge and discharge state of the charge and discharge circuit to the second input terminal of the first comparator according to whether the dog feeding signal is received, thereby changing the input voltage of the second input terminal of the first comparator. Finally, based on the comparison and analysis of the reference voltage and the input voltage, the output terminal of the first comparator feeds back the corresponding level signal to realize the monitoring and restart control of the object to be monitored connected thereto. The watchdog circuit constructed in this application has circuit parameters that can be flexibly adjusted according to actual needs. While combining the operating state of the dog feeding circuit to realize the monitoring and restart control functions, it can also have low power consumption and can meet the low power consumption operation requirements of equipment with high power consumption requirements.

[0010] In some embodiments, the voltage divider circuit includes a resistor voltage divider unit and a delay unit, the resistor voltage divider unit is connected to the output end of the first comparator and the power supply respectively, the resistor voltage divider unit is also connected to the delay unit, and the delay unit is connected to the first input end of the first comparator.

[0011] In the above solution, the voltage divider circuit includes two parts: a resistor voltage divider unit and a delay unit. While realizing the voltage divider function, it can also maintain the output state of the first comparator within a certain period of time, thereby improving the operational reliability of the watchdog circuit.

[0012] In some embodiments, the resistance divider unit includes a first resistor and a second resistor, the first end of the first resistor is connected to the power supply, the second end of the first resistor is connected to the first end of the second resistor and the delay unit, and the second end of the second resistor is connected to the output end of the first comparator.

[0013] In the above scheme, the resistor voltage divider unit can be set to the form of a resistor voltage divider, the circuit structure is simple, and when the voltage division ratio remains unchanged, the resistance values ​​of the first resistor and the second resistor can be adjusted, while effectively saving circuit costs, and further reducing the power consumption of the watchdog circuit.

[0014] And / or, in some embodiments, the delay unit includes a third resistor and a first capacitor, the first end of the third resistor is connected to the first end of the first capacitor and the first input end of the first comparator, the first end of the first capacitor is also connected to the resistor divider unit, and the second end of the first capacitor and the second end of the third resistor are grounded.

[0015] In the above solution, the delay unit can be set as an RC (resistance-capacitance) delay unit, so that the output state of the first comparator can be maintained unchanged for a certain period of time when the charge and discharge state changes, thereby improving the operational reliability of the watchdog circuit.

[0016] In some embodiments, the charge and discharge circuit includes a fourth resistor and a second capacitor, the first end of the fourth resistor is connected to the output end of the first comparator, the second end of the fourth resistor is connected to the first end of the second capacitor and the second input end of the first comparator, the first end of the second capacitor is also connected to the dog feeding circuit, and the second end of the second capacitor is grounded.

[0017] In the above scheme, the resistor-capacitor charging circuit is constructed using a fourth resistor and a second capacitor. The second capacitor can be charged or discharged under different output controls of the dog feeding circuit, thereby changing the output state of the first comparator, and has high charging and discharging operation reliability.

[0018] In some embodiments, the dog feeding circuit includes an AC coupling circuit, a charging device and a first switching device. The input end of the AC coupling circuit is used to receive a dog feeding signal, the output end of the AC coupling circuit is connected to the first end of the charging device and the control end of the first switching device, the input end of the first switching device is connected to the charging and discharging circuit, and the second end of the charging device and the output end of the first switching device are grounded.

[0019] In the above solution, the dog feeding circuit charges and discharges the charging device according to the received dog feeding signal, thereby changing the on-off state of the first switching device, and then changing the charging and discharging state of the charging and discharging circuit on the second input terminal of the first comparator. The control method is simple and the control efficiency is high.

[0020] In some embodiments, the watchdog circuit further includes an enabling circuit connected to the charging and discharging circuit.

[0021] The above scheme also connects an enabling circuit to the charging and discharging circuit of the hysteresis comparator circuit. The enabling circuit can provide a discharge channel for the charging and discharging circuit, so that the input voltage of the second input terminal of the comparator is maintained at 0V, realizing the enabling function of the watchdog circuit and further improving the operating reliability of the watchdog circuit.

[0022] In some embodiments, the enabling circuit includes a seventh resistor and a second switching device, the first end of the seventh resistor is connected to the control end of the second switching device, the control end of the second switching device is used to input an enabling signal, the output end of the second switching device is connected to a voltage divider circuit, and the second end of the seventh resistor and the output end of the second switching device are grounded.

[0023] In the above solution, the enabling circuit can be constructed by the seventh resistor and the second switch device, the circuit structure is simple, and the circuit cost can be effectively saved.

[0024] In some embodiments, the enabling circuit further includes an inverter circuit, the control terminal of the second switching device is connected to the output terminal of the inverter circuit, and the input terminal of the inverter circuit is used to input the enabling signal.

[0025] The above solution can also connect an inverting circuit to the enabling circuit, so as to drive the enabling circuit with an opposite level signal, so that the enabling circuit better matches the output of the object to be monitored, thereby improving the applicability of the watchdog circuit.

[0026] In some embodiments, the watchdog circuit also includes a first power-on reset circuit and a logic processing circuit, the output end of the first comparator is connected to the first input end of the logic processing circuit, the first power-on reset circuit is connected to the second input end of the logic processing circuit, and the output end of the logic processing circuit is used to output a logic processing signal.

[0027] The above solution can realize reset control of the watchdog circuit by configuring the first power-on reset circuit for the watchdog circuit, thereby further improving the operational reliability of the watchdog circuit.

[0028] In some embodiments, the first power-on reset circuit includes a resistor voltage divider circuit, a resistor-capacitor charging circuit and a second comparator, the resistor-capacitor charging circuit is connected to the first input terminal of the second comparator, the resistor voltage divider circuit is connected to the second input terminal of the second comparator, and the output terminal of the second comparator is connected to the second input terminal of the logic processing circuit.

[0029] In the above scheme, the first power-on reset circuit is constructed by a second comparator, a resistor voltage divider circuit and a resistor-capacitor charging circuit. The second comparator performs comparative analysis based on the output of the resistor voltage divider circuit and the output of the resistor-capacitor charging circuit to provide a reset level for the watchdog circuit, which has high reset control reliability.

[0030] In some embodiments, the resistor-capacitor charging circuit includes an eighth resistor and a fifth capacitor connected in series, the connection point of the eighth resistor and the fifth capacitor is connected to the first input terminal of the second comparator, the end of the eighth resistor away from the fifth capacitor is connected to the power supply, and the end of the fifth capacitor away from the eighth resistor is grounded.

[0031] In the above scheme, the resistor-capacitor charging circuit is constructed by the eighth resistor and the fifth capacitor, and the common connection point of the two is connected to the first input terminal of the second comparator to provide the required voltage for the first input terminal of the second comparator. The circuit structure is simple and can effectively save circuit costs.

[0032] And / or, in some embodiments, the resistance divider circuit includes a ninth resistor and a tenth resistor connected in series, the connection point between the ninth resistor and the tenth resistor is connected to the second input terminal of the second comparator, the end of the ninth resistor away from the tenth resistor is connected to the power supply, and the end of the tenth resistor away from the ninth resistor is grounded.

[0033] In the above scheme, the voltage divider circuit is constructed by connecting the ninth resistor and the tenth resistor in series, and the common connection point between the ninth resistor and the tenth resistor is connected to the second input terminal of the second comparator to provide the required reference voltage for the second input terminal of the second comparator. The circuit structure is simple and can effectively save circuit costs.

[0034] In some embodiments, the logic processing circuit includes a first diode and a second diode, the cathode of the first diode is connected to the output end of the first comparator, the cathode of the second diode is connected to the first power-on reset circuit, the anode of the first diode is connected to the anode of the second diode, and the common end formed by the anode of the first diode and the anode of the second diode serves as the output end of the logic processing circuit.

[0035] The above solution uses two diodes to build a logic processing circuit to realize the logic and function, which can effectively reduce the circuit cost.

[0036] In some embodiments, the logic processing circuit further includes a pull-up resistor and a lower-end capacitor, wherein the first end of the pull-up resistor is connected to the power supply, the second end of the pull-up resistor is connected to the common end, the first end of the lower-end capacitor is connected to the common end, and the second end of the lower-end capacitor is grounded.

[0037] The above solution further connects a pull-up resistor and a lower-end capacitor between the output of the logic processing circuit and the object to be monitored, thereby improving the operational reliability of the logic processing circuit.

[0038] The present application also provides an electronic power device, including a controller and the above-mentioned watchdog circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive work. In the drawings:

[0040] FIG1 is a schematic diagram of the structure of a watchdog circuit in some embodiments of the present application;

[0041] FIG2 is a schematic diagram of the structure of a watchdog circuit in some other embodiments of the present application;

[0042] FIG3 is a schematic diagram of the structure of a watchdog circuit in some other embodiments of the present application;

[0043] FIG4 is a schematic diagram of the structure of a watchdog circuit in some further embodiments of the present application;

[0044] FIG5 is a schematic diagram of the structure of a watchdog circuit in some other embodiments of the present application;

[0045] FIG6 is a schematic diagram of the structure of a watchdog circuit in some other embodiments of the present application;

[0046] FIG. 7 is a schematic diagram of a pull-up voltage-current curve of a Schottky diode in some embodiments of the present application.

[0047] Figure 1: 101-dog feeding circuit, 103-hysteresis comparator circuit, 202-voltage divider circuit, 204-charge and discharge circuit, 102-first comparator; 2022-resistance voltage divider unit, 2024-hysteresis unit; R1-first resistor, R2-second resistor, R3-third resistor, C1-first capacitor; R4-fourth resistor, C2-second capacitor; 401-AC coupling circuit, 402-switch operation protection circuit, C3-charging device, R5-first capacitor Five resistors, D1 - unidirectional conducting switch, Q1 - first switch, R6 - sixth resistor, C4 - fourth capacitor; 502 - enable circuit, Q2 - second switch, R7 - seventh resistor; 504 - first power-on reset circuit, 506 - logic processing circuit; 501 - second comparator, 503 - resistor-capacitor charging circuit, 505 - resistor voltage divider circuit; R8 - eighth resistor, C5 - fifth capacitor, R9 - ninth resistor, R10 - tenth resistor. DETAILED DESCRIPTION

[0048] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0050] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0051] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0052] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0053] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0054] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0055] Currently, market trends indicate that electronic power equipment is increasingly moving toward automation and intelligence. Configuring controllers for these devices and integrating their control logic to control their operation has become the mainstream control method. Controllers typically require software control programs written to meet actual operational requirements. The stable operation of these software control programs in real-world scenarios is essential for maintaining the normal operation of electronic power equipment.

[0056] During actual operation, interference from external electromagnetic fields can easily cause data corruption in the controller, leading to program pointer errors, loss of program area, incorrect program instruction output, and even infinite loops, interrupting normal program execution. Ultimately, the controller cannot operate normally, causing the entire electronic power equipment to stall, resulting in unpredictable consequences.

[0057] Therefore, currently, a software watchdog program is written into the controller, or a hardware watchdog circuit is built externally to monitor the controller's program execution and promptly restart the controller if a control error occurs. Hardware watchdog circuits are generally built using a specific watchdog chip, which consumes relatively high and fixed power. This cannot meet the power requirements of devices with high power requirements, such as those powered by electricity or batteries.

[0058] To address this issue, research has found that a hysteresis comparator circuit can be constructed using a voltage divider circuit, a charge-discharge circuit, and a comparator with flexible and adjustable device parameters. Connecting the watchdog circuit to the comparator of the hysteresis comparator circuit allows the controller to monitor and restart by changing the comparator's output based on the input state of the watchdog circuit. In this way, in practical scenarios, adjusting the watchdog circuit's device parameters can reduce its power consumption to a certain extent.

[0059] Based on the above considerations, a voltage divider circuit, a charge-discharge circuit, and a first comparator can be used to construct a hysteresis comparison circuit, and the input end of the dog feeding circuit and the output end of the first comparator are respectively connected to the object to be monitored. During actual operation, the voltage divider circuit can input a reference voltage to the first input end of the first comparator. The dog feeding circuit adjusts the charge and discharge state of the charge and discharge circuit to the second input end of the first comparator according to the output state of the object to be monitored, that is, its own input state, and changes the input voltage of the second input end of the first comparator. Finally, the first comparator performs a comparative analysis based on the reference voltage and the input voltage, and feeds back a corresponding level signal to the object to be monitored, thereby realizing monitoring and restart control of the object to be monitored.

[0060] Through the watchdog circuit constructed above, the circuit parameters can be flexibly adjusted according to actual needs, so as to realize the monitoring and restart control functions in combination with the operating status of the dog feeding circuit, while also having low power consumption, which can meet the low-power operation requirements of equipment with higher power consumption requirements.

[0061] The watchdog circuit provided in the embodiment of the present application is used in electronic power equipment. Optionally, the watchdog circuit is connected to a control device or controller that integrates a control program and performs operation control on the electronic power equipment, such as the MCU, DSP or FPGA of the electronic power equipment, etc., without specific limitation.

[0062] The specific type of electronic power equipment is not limited and can be any electronic power equipment equipped with a controller or control device. For example, in some embodiments, it can be related electronic power equipment in an energy storage system, such as various power supply devices, battery power supply devices, etc., without specific limitation.

[0063] Please refer to Figure 1. The present application provides a watchdog circuit, including a dog feeding circuit 101 and a hysteresis comparator circuit 103. The hysteresis comparator circuit 103 includes a voltage divider circuit 202, a charge and discharge circuit 204 and a first comparator 102; the first input end of the first comparator 102 is connected to the output end of the first comparator 102 through the voltage divider circuit 202, the second input end of the first comparator 102 is connected to the output end of the first comparator 102 through the charge and discharge circuit 204, and the dog feeding circuit 101 is connected to the charge and discharge circuit 204.

[0064] The input end of the dog feeding circuit 101 and the output end of the first comparator 102 are respectively used to connect to the object to be monitored. Among them, the object to be monitored is a controller that needs to be monitored by the watchdog circuit and restarted by the watchdog circuit when an error occurs in the control program. The dog feeding circuit 101 is a circuit used to receive the dog feeding signal and adjust different output states according to the different reception conditions of the dog feeding signal. The dog feeding signal is a signal sent regularly by the object to be monitored to detect whether an error has occurred in the control program of the object to be monitored. Accordingly, if the dog feeding circuit 101 does not receive the dog feeding signal sent by the object to be monitored within a certain period of time, it means that an error has occurred in the control program of the object to be monitored.

[0065] The hysteresis comparator circuit 103 compares two input signals, outputs a high-level signal or a low-level signal based on the comparison result, and then performs another comparison after a hysteresis (delay) period. The first comparator 102 compares the two input signals and outputs a high-level signal or a low-level signal. The voltage divider circuit 202 divides the power supply voltage into a suitable reference voltage and transmits it as a reference signal to the first input terminal of the first comparator 102. The charge-discharge circuit 204 uses the output of the dog feeding circuit 101 to implement a charging or discharging function, thereby changing the input voltage at the second input terminal of the first comparator 102.

[0066] In the solution of this embodiment, when the dog feeding circuit 101 receives the dog feeding signal, the dog feeding circuit 101 is activated, so that the charge and discharge circuit 204 connected to the second input terminal (which may be the negative terminal) of the first comparator 102 is grounded, and the input voltage of the second input terminal of the first comparator 102 is pulled down. The reference voltage of the first input terminal (which may be the positive terminal) of the first comparator 102 is higher than the input voltage of the second input terminal. After comparison, the first comparator 102 outputs a first level signal (which may be a high level signal).

[0067] When the dog feeding circuit 101 does not receive the dog feeding circuit 101, the dog feeding circuit 101 will not operate. At this time, the second input terminal of the first comparator 102 is charged under the action of the charge and discharge circuit 204, and eventually the input voltage of the second input terminal is greater than the reference voltage. After comparison, the first comparator 102 outputs a second level signal (opposite to the first level signal).

[0068] Correspondingly, in actual scenarios, it is only necessary to configure the monitored object to operate normally upon receiving a first level signal and to restart upon receiving a second level signal, thereby enabling monitoring and restart control of the monitored object to be achieved through the watchdog circuit.

[0069] The watchdog circuit is constructed using a voltage divider circuit 202, a charge-discharge circuit 204, and a first comparator 102 to form a hysteresis comparator circuit 103. The first input of the first comparator 102 is connected to the output of the first comparator 102 via the voltage divider circuit 202, and the second input of the first comparator 102 is connected to the output of the first comparator 102 via the charge-discharge circuit 204. The dog feeding circuit 101 is connected to the charge-discharge circuit 204. In actual operation, a reference voltage can be input to the first input of the first comparator 102 through the voltage divider circuit 202. The dog feeding circuit 101 adjusts the charge and discharge state of the second input of the first comparator 102 by the charge-discharge circuit 204 according to whether the dog feeding signal is received, thereby changing the input voltage of the second input of the first comparator 102. Finally, the output of the first comparator 102 compares and analyzes the reference voltage and the input voltage, and feeds back a corresponding level signal to achieve monitoring and restart control of the connected monitored object. The watchdog circuit constructed in this application has circuit parameters that can be flexibly adjusted according to actual needs. While combining the operating status of the dog feeding circuit 101 to realize the monitoring and restart control functions, it can also have low power consumption and can meet the low-power operation requirements of devices with higher power consumption requirements.

[0070] Furthermore, in some embodiments, in order to further reduce the power consumption of the watchdog circuit, a first comparator 102 with a quiescent current of nanoamperes can be used to build a hysteresis comparison circuit. The quiescent current is the current when there is no signal input, that is, the current consumed by the first comparator 102 itself when it is not affected by external factors. The nanoampere (nA) level means that the quiescent current is greater than or equal to 1nA and less than 1000nA. There is no specific limitation and it can be selected based on actual conditions. In this way, the power consumption of the watchdog circuit can be further reduced during the operation of the watchdog circuit, so that the watchdog circuit can better match the low-power operation requirements of devices with higher power consumption requirements.

[0071] Referring to Figure 2, in some embodiments, the voltage divider circuit 202 includes a resistor voltage divider unit 2022 and a delay unit 2024. The resistor voltage divider unit 2022 is respectively connected to the output terminal of the first comparator 102 and the power supply (VCC). The resistor voltage divider unit 2022 is also connected to the delay unit 2024, and the delay unit 2024 is connected to the first input terminal of the first comparator 102.

[0072] The resistor divider unit 2022 is a circuit unit constructed using resistors and having a voltage divider function. The delay unit 2024 is a circuit unit having a delay function. In this embodiment, the resistor divider unit 2022 is connected to the first input terminal of the first comparator 102, providing a reference voltage of an appropriate magnitude to the first input terminal through the resistor divider function. Simultaneously, the delay unit 2024 is also provided at the first input terminal of the first comparator 102 to delay the voltage change time of the first input terminal, thereby maintaining the output of the first comparator 102 unchanged for a period of time, thereby achieving the output state maintenance function of the first comparator 102.

[0073] It should be noted that the specific structure of the voltage divider circuit 202 is not unique. In other embodiments, the voltage divider circuit can also be constructed by using a potentiometer voltage divider unit and a delay unit. Furthermore, in other embodiments, the voltage divider circuit 202 can also include only a resistor voltage divider unit, and the selection can be made based on actual needs.

[0074] In the above solution, the voltage divider circuit 202 includes a resistor voltage divider unit 2022 and a delay unit 2024. While achieving the voltage divider function, it can also maintain the output state of the first comparator 102 within a certain period of time, thereby improving the operational reliability of the watchdog circuit.

[0075] Please refer to Figure 3. In some embodiments, the resistance divider unit 2022 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the power supply, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the delay unit 2024, and the second end of the second resistor R2 is connected to the output end of the first comparator 102.

[0076] And / or, in some embodiments, the delay unit 2024 includes a third resistor R3 and a first capacitor C1, the first end of the third resistor R3 is connected to the first end of the first capacitor C1 and the first input end of the first comparator 102, the first end of the first capacitor C1 is also connected to the resistor divider unit 2022, and the second end of the first capacitor C1 and the second end of the third resistor R3 are grounded.

[0077] The first resistor R1, the second resistor R2, and the third resistor R3 may each comprise a single resistor, or may comprise multiple resistors connected in series and / or in parallel. The specific configuration is not limited and may be selected based on actual needs. Similarly, the first capacitor C1 may be a single capacitor, or may be a capacitor assembly constructed by connecting multiple capacitors in series and / or in parallel.

[0078] It can be understood that the resistors and capacitors appearing in the following embodiments can all be understood as a single resistor, a single capacitor, or a component formed by connecting multiple resistors in series and / or in parallel, or a component formed by connecting multiple capacitors in series and / or in parallel, and the details will not be repeated here.

[0079] In some embodiments, the resistor divider unit 2022 includes a first resistor R1 and a second resistor R2, and the delay unit 2024 includes a third resistor R3 and a first capacitor C1. In this case, the first end of the first capacitor C1 is connected to the second end of the first resistor R1 and the first end of the second resistor R2. In the solution of this embodiment, when the dog feeding circuit 101 receives a dog feeding signal, the dog feeding circuit 101 is activated so that the charge and discharge circuit 204 is in a discharge state. At this time, the input end of the first comparator 102 can be regarded as the first resistor R1 connected in parallel with the second resistor R2, and then connected in series with the third resistor R3. Correspondingly, the reference voltage input to the first input end of the first comparator 102 is: VCC*R3 / (R1||R2+R3), where VCC represents the power supply voltage, R1 represents the resistance value of the first resistor R1, R2 represents the resistance value of the second resistor R2, R3 represents the resistance value of the third resistor R3, and R1||R2 represents the resistance value of the first resistor R1 and the second resistor R2 in parallel.

[0080] It should be noted that in some embodiments, to minimize the power consumption of the watchdog circuit, the resistance value of the first resistor R1 and the resistance value of the second resistor R2 are both in the megaohm level, that is, greater than or equal to 1 megaohm and less than or equal to 1000 megaohm.

[0081] When no dog feeding signal is input, the first input terminal of the first comparator 102 can be regarded as the second resistor R2 and the third resistor R3 connected in parallel, and then connected in series with the first resistor R1. Correspondingly, the reference voltage input to the first input terminal of the first comparator 102 is: VCC*(R3||R2) / ((R3||R2)+R1).

[0082] In the above solution, the resistor voltage divider unit 2022 can be set to the form of a resistor voltage divider, which has a simple circuit structure. When the voltage divider ratio remains unchanged, the resistance values ​​of the first resistor R1 and the second resistor R2 can be adjusted, which effectively saves circuit cost and further reduces the power consumption of the watchdog circuit.

[0083] The delay unit 2024 can be configured as an RC (resistance-capacitance) delay unit, so that the output state of the first comparator 102 can be maintained unchanged for a certain period of time when the charge and discharge state changes, thereby improving the operational reliability of the watchdog circuit.

[0084] Referring to Figure 3, in some embodiments, the charge and discharge circuit 204 includes a fourth resistor R4 and a second capacitor C2. The first end of the fourth resistor R4 is connected to the output end of the first comparator 102, the second end of the fourth resistor R4 is connected to the first end of the second capacitor C2 and the second input end of the first comparator 102, the first end of the second capacitor C2 is also connected to the dog feeding circuit 101, and the second end of the second capacitor C2 is grounded.

[0085] When the dog feeding circuit 101 receives a dog feeding signal, the dog feeding circuit 101 operates, causing the first end of the second capacitor C2 to be grounded through the dog feeding circuit 101. At this time, the second capacitor C2 discharges to ground, ultimately causing the input voltage at the second input end of the first comparator 102 to be less than the reference voltage, and the first comparator 102 maintains the output of the first level signal. In the absence of a dog feeding signal, the power supply voltage charges the second capacitor C2 through the fourth resistor R4. As the charging time increases, the input voltage becomes greater than the reference voltage, and the first comparator 102 outputs a second level signal.

[0086] In the above solution, the charge and discharge circuit 204 is constructed using the fourth resistor R4 and the second capacitor C2. The second capacitor C2 can be charged or discharged under different output controls of the dog feeding circuit 101, thereby changing the output state of the first comparator 102, and has high charge and discharge operation reliability.

[0087] In some embodiments, the resistance of the voltage divider resistor of the voltage divider circuit 202 is adjustable.

[0088] The voltage divider resistor values ​​are the resistance values ​​of the voltage divider resistors involved in the voltage divider circuit 202. It should be noted that when adjusting the voltage divider resistor values, the voltage divider ratio must be maintained constant, and the resistance values ​​of the various voltage divider resistors must be increased simultaneously in the same ratio. This minimizes the power consumption of the resistor divider circuit 202 while maintaining the voltage divider function. For example, in some embodiments, the voltage divider ratio is R3 / (R1||R2+R3). When adjusting the voltage divider resistor values, R1, R2, and R3 can be increased tenfold simultaneously, i.e., adjusted to 10*R3 / (10*R1||10*R2+10*R3).

[0089] The above solution can change the power consumption of the watchdog circuit by adjusting the voltage divider resistance value of the resistor voltage divider circuit 202, and the adjustment is highly convenient.

[0090] And / or, in some embodiments, the resistance and capacitance of the charge-discharge circuit 204 are adjustable.

[0091] In the RC charging circuit, the charging formula is τ = RC, where V C is the capacitor charging voltage, τ is the time constant, V cc is the power supply voltage, I is the current, t is the time, R represents the resistance value, C represents the capacitance value, and e represents the natural constant. As the charging time increases, the capacitor charging voltage will gradually increase until it exceeds the reference voltage, changing the output level signal of the first comparator 102. Therefore, in actual scenarios, the output level signal of the first comparator 102 can be maintained by changing the RC charging and discharging time, thereby realizing a hysteresis comparison function.

[0092] For example, in some embodiments, the capacitor charging voltage reaches 63.2% of the power supply voltage after 1τ charging time, reaches 86.5% of the power supply voltage after 2τ charging time, and reaches 99.24% of the power supply voltage after 5τ charging time. In the actual charging process, since the reference voltage is lower than the power supply voltage due to the resistor voltage divider, after approximately 2τ charging time, the input voltage of the second input terminal of the first comparator 102 is greater than the reference voltage of the first input terminal.

[0093] The above solution can change the charge and discharge time of the charging circuit by adjusting the resistance value and the capacitance value in the charging and discharging circuit 204 to meet the requirements of different scenarios and improve the operational reliability of the watchdog circuit.

[0094] Please refer to Figure 4. In some embodiments, the dog feeding circuit 101 includes an AC coupling circuit 401, a charging device C3, and a first switching device Q1. The input end of the AC coupling circuit 401 is used to receive a dog feeding signal. The output end of the AC coupling circuit 401 is connected to the first end of the charging device C3 and the control end of the first switching device Q1. The input end of the first switching device Q1 is connected to the charge and discharge circuit 204. The second end of the charging device C3 and the output end of the first switching device Q1 are grounded.

[0095] The AC coupling circuit 401 is a circuit that blocks DC and passes AC, thereby coupling the monitored object with the dog feeding circuit 101. The charging device C3 is a device with the function of storing and releasing electric energy. Its specific type is not unique. It can be a single capacitor, multiple capacitors in series / parallel, or a battery, etc., and is not specifically limited. For ease of understanding, the following embodiments can all consider the charging device C3 to be a third capacitor. In the solution of this embodiment, the dog feeding signal input to the dog feeding circuit 101 is essentially a pulse signal. At the rising edge of the pulse signal, the charging device C3 is charged, the voltage of the charging device C3 increases, and the first switch device Q1 is controlled to turn on. The second capacitor C2 in the charge and discharge circuit 204 is grounded through the first switch device Q1 and discharged to the ground. The input voltage of the second input terminal of the first comparator 102 is lower than the reference voltage, and the first comparator 102 outputs a first level signal.

[0096] It should be noted that the specific type of the first switching device Q1 is not limited. In some embodiments, the first switching device Q1 includes a field-effect transistor. By using low-power field-effect transistors to construct the dog feeding circuit 101, the power consumption of the dog feeding circuit 101 can be effectively reduced.

[0097] In the above scheme, the dog feeding circuit 101 charges and discharges the charging device C3 according to the received dog feeding signal, thereby changing the on-off state of the first switching device Q1, and further changing the charging and discharging state of the second input terminal of the first comparator 102 by the charging and discharging circuit 204. The control method is simple and the control efficiency is high.

[0098] It is understood that in other embodiments, the AC coupling circuit 401 in the dog feeding circuit 101 can also be replaced with a capacitive coupling circuit or other types of coupling circuits, as long as the coupling of the monitored object can be achieved. Furthermore, in other embodiments, the dog feeding circuit can also be constructed in other forms, for example, only including the charging device C3 and the first switching device Q1, as long as the second input terminal of the first comparator 102 enters different operating states when there is a dog feeding signal input and when there is no dog feeding signal input, and ultimately the first comparator 102 outputs different types of level signals.

[0099] Please refer to Figure 4. In some embodiments, the dog feeding circuit 101 further includes a switch operation protection circuit 402. A first end of the switch operation protection circuit 402 is connected to the first end of the charging device C3 and the control end of the first switching device Q1. A second end of the switch operation protection circuit 402 is connected to the second end of the charging device C3 and the output end of the first switching device Q1.

[0100] The switch operation protection circuit 402 is a circuit that protects the first switching device Q1 during the operation of the dog feeding circuit 101. The specific type of the switch operation protection circuit 402 is not limited to a single type and can be a circuit with a current limiting protection function or a circuit with a negative voltage suppression function, etc.

[0101] In the above solution, a switch operation protection circuit 402 is further provided between the first switch device Q1 and the charging device C3 to protect the safe operation of the first switch device Q1 and improve the operation safety of the dog feeding circuit 101.

[0102] Referring to FIG. 4 , in some embodiments, the switch operation protection circuit 402 includes a fifth resistor R5 , wherein a first end of the fifth resistor R5 is connected to a first end of the charging device C3 and a control end of the first switching device Q1 , and a second end of the fifth resistor R5 is connected to a second end of the charging device C3 and an output end of the first switching device Q1 .

[0103] In the above solution, a fifth resistor R5 is further provided between the first switching device Q1 and the charging device C3. The fifth resistor R5 reduces the occurrence of abnormal interference to the first switching device Q1 and improves the operating stability of the first switching device Q1.

[0104] And / or, in some embodiments, referring to FIG. 4 , the switch operation protection circuit 402 includes a unidirectional conducting switch element D1, a cathode of the unidirectional conducting switch element D1 connected to a first end of the charging device C3 and a control end of the first switching device Q1, and an anode of the unidirectional conducting switch element D1 connected to a second end of the charging device C3 and an output end of the first switching device Q1.

[0105] The unidirectional conducting switch element D1 is a unidirectional conducting switch element. The specific type of the unidirectional conducting switch element D1 is not limited to a single type. In some embodiments, a diode can be used as the unidirectional conducting switch element. Alternatively, one or more diodes can be selected based on actual needs to form the unidirectional conducting switch element D1. This is not a limitation herein.

[0106] In the above solution, a unidirectional conducting switch D1 is further provided between the first switching device Q1 and the charging device C3, thereby providing a discharge path, reducing the possibility of the first switching device Q1 generating a negative voltage, and improving the operating safety of the first switching device Q1.

[0107] In some embodiments, the switch operation protection circuit 402 may include both the fifth resistor R5 and the unidirectional switching device D1. In this embodiment, the fifth resistor R5 and the unidirectional switching device D1 are sequentially connected in parallel between the charging device C3 and the first switching device Q1. The fifth resistor R5 acts as a pull-down resistor to reduce the possibility of interference and abnormality in the first switching device Q1. The unidirectional switching device D1 provides a discharge path during the falling edge of the pulse to discharge the output terminal of the first switching device Q1.

[0108] 4 , in some embodiments, the AC coupling circuit 401 includes a sixth resistor R6 and a fourth capacitor C4 connected in series. An end of the sixth resistor R6 away from the fourth capacitor C4 is used to receive a dog feeding signal. An end of the fourth capacitor C4 away from the sixth resistor R6 is also connected to a first end of the charging device C3.

[0109] As shown above, the dog feeding signal input to the dog feeding circuit 101 is essentially a pulse signal. At the falling edge of the pulse signal, the fourth capacitor C4 in the AC coupling circuit 401 discharges to the outside. At this time, the discharge path provided by the unidirectional conductive switch D1 is used to effectively reduce the possibility of negative voltage generated by the first switching device Q1.

[0110] The above solution uses a series circuit constructed by connecting the sixth resistor R6 and the fourth capacitor C4 in series as the AC coupling circuit 401 to achieve the function of passing AC and blocking DC, which has the advantages of simple circuit structure and saving circuit cost.

[0111] Please refer to FIG. 5 . In some embodiments, the watchdog circuit further includes an enabling circuit 502 . The enabling circuit 502 is connected to the charge-discharge circuit 204 .

[0112] The enabling circuit 502 is a circuit for enabling and controlling the watchdog function. The solution of this embodiment may further include the enabling circuit 502, depending on actual operational requirements. The enabling function of the enabling circuit 502 can ground the charge-discharge circuit 204 through the enabling circuit 502, thereby maintaining the voltage at the second input terminal of the first comparator 102 at 0V (volts). The output terminal of the first comparator 102 continuously outputs a first-level signal and cannot trigger the output of a second-level signal.

[0113] In the above scheme, an enabling circuit 502 is also connected to the hysteresis comparator circuit 103. The enabling circuit 502 can provide a discharge channel for the charge and discharge circuit 204, so that the input voltage of the second input terminal of the comparator is maintained at 0V, thereby realizing the enabling function of the watchdog circuit and further improving the operating reliability of the watchdog circuit.

[0114] 5 , in some embodiments, the enabling circuit 502 includes a seventh resistor R7 and a second switching device Q2. A first end of the seventh resistor R7 is connected to a control end of the second switching device Q2. The control end of the second switching device Q2 is used to input an enabling signal. An output end of the second switching device Q2 is connected to the voltage divider circuit 204. A second end of the seventh resistor R7 and an output end of the second switching device Q2 are grounded.

[0115] The specific type of enabling circuit 502 is not limited. In this embodiment, the seventh resistor R7 and the second switch device Q2 are used to implement the enabling function while reducing the possibility of interference with the second switch device Q2 and improving the operating reliability of the second switch device Q2. It is understood that in other embodiments, a separate second switch device Q2 can also be used as the enabling circuit 502, or an enabling chip can be used as the enabling circuit 502, without specific limitation.

[0116] When it is necessary to turn off the watchdog function through enable control, the enable signal output causes the second switch device Q2 to be turned on, and the charge and discharge circuit 204 is grounded through the second switch device Q2. The second capacitor C2 in the charge and discharge circuit 204 can be grounded through the second switch device Q2. The second input terminal of the first comparator 102 maintains the input at 0V. Regardless of whether the watchdog feeding signal is received or not, the output of the hysteresis comparator circuit 103 continues to maintain the first level state, and the watchdog function is turned off.

[0117] It should be noted that the specific type of the second switching device Q2 is not limited. In some embodiments, the second switching device Q2 includes a field-effect transistor. By using a low-power field-effect transistor to form the enabling circuit 502, the power consumption of the enabling circuit 502 can be effectively reduced compared to using a triode as the second switching device Q2.

[0118] In the above solution, the enabling circuit 502 can be constructed by the seventh resistor R7 and the second switch device Q2, which has a simple circuit structure and can effectively save circuit costs.

[0119] In some embodiments, the enabling circuit 502 further includes an inverting circuit, the control terminal of the second switching device Q2 is connected to the inverting circuit, and the inverting circuit is used to input an enabling signal.

[0120] In actual use scenarios, you can choose between high-level enable and low-level enable based on actual usage needs. For example, if the enable signal output by the monitored object is low-level and the enable circuit 502 is high-level enabled, to implement the enable function, an inverter circuit is required to convert the low-level signal output by the monitored object into a high-level signal. If the enable circuit 502 is also low-level enabled, there is no need to set up an inverter circuit.

[0121] It is understandable that the specific form of the inverting circuit is not unique. In some embodiments, it can be an inverter or an additional field effect transistor to achieve the inverting function, which is not specifically limited.

[0122] In the above solution, an inverting circuit may be connected to the enabling circuit 502 to drive the enabling circuit 502 with an opposite level signal, so that the enabling circuit 502 better matches the output of the monitored object and improves the applicability of the watchdog circuit.

[0123] Please refer to Figure 5. In some embodiments, the watchdog circuit further includes a first power-on reset circuit 504 and a logic processing circuit 506. The output end of the first comparator 102 is connected to the first input end of the logic processing circuit 506, the first power-on reset circuit 504 is connected to the second input end of the logic processing circuit 506, and the output end of the logic processing circuit 506 is used to output a logic processing signal.

[0124] Initial power-on reset circuit 504 is a circuit that resets the output of the watchdog circuit to a specific level signal when the watchdog circuit is powered on for the first time. In this embodiment, when the watchdog circuit is powered on for the first time, the output level signal of hysteresis comparator circuit 103 is logically operated with the output level signal of initial power-on reset circuit 504 to ultimately output a corresponding level signal.

[0125] The above solution can realize reset control of the watchdog circuit by configuring the first power-on reset circuit 504 for the watchdog circuit, thereby further improving the operational reliability of the watchdog circuit.

[0126] Please refer to Figure 5. In some embodiments, the first power-on reset circuit 504 includes a resistor voltage divider circuit 505, a resistor-capacitor charging circuit 503 and a second comparator 501. The resistor-capacitor charging circuit 503 is connected to the first input terminal of the second comparator 501, the resistor voltage divider circuit 505 is connected to the second input terminal of the second comparator 501, and the output terminal of the second comparator 501 is connected to the second input terminal of the logic processing circuit 506.

[0127] The first power-on reset circuit 504 includes a voltage divider input part, a delayed charging part and a second comparator 501. Through the voltage division of the resistor voltage divider circuit 505, a reference voltage can be provided for the second input terminal of the second comparator 501. Therefore, the charging and discharging of the resistor-capacitor charging circuit 503 can change the input voltage of the first input terminal of the first comparator 102, thereby changing the output level signal of the second comparator 501.

[0128] It is understood that in other embodiments, the voltage-dividing input portion of the power-on reset circuit 504 may also be implemented using a potentiometer or other method. The delayed charging portion of the power-on reset circuit 504 may also be implemented using a time-delay relay and an energy storage device (e.g., an energy storage battery), without limitation.

[0129] In some embodiments, the first input terminal of the second comparator 501 is a positive terminal, and the second input terminal is a negative terminal. First, when the first power-on reset circuit 504 is powered on, the resistor-capacitor charging circuit 503 begins charging. The input voltage at the first input terminal of the second comparator 501 is lower than the input voltage at the second input terminal of the second comparator 501. At this time, the second comparator 501 outputs a low-level signal. As the charging time increases, the input voltage at the first input terminal of the second comparator 501 will become greater than the input voltage at the second input terminal. After this, the second comparator 501 will output a high-level signal. In other words, the first power-on reset circuit 504 can maintain the output of the low-level signal from the second comparator 501 for a period of time. By performing a logical operation on the low-level signal and the level signal output by the hysteresis comparator circuit 103, the output of a specific level signal is maintained. For example, the low-level signal is logically ANDed with the level signal output by the hysteresis comparator circuit 103, thereby maintaining the output of the low-level signal for a period of time.

[0130] In the above scheme, the first power-on reset circuit 504 is constructed by the second comparator 501, the resistor voltage divider circuit 505 and the resistor-capacitor charging circuit 503. The second comparator 501 combines the output of the resistor voltage divider circuit 505 and the output of the resistor-capacitor charging circuit 503 for comparison and analysis to provide a reset level for the watchdog circuit, which has high reset control reliability.

[0131] In some embodiments, the voltage divider resistance value of the resistor divider circuit 505 is adjustable.

[0132] The voltage-dividing resistor value is the resistance value of the voltage-dividing resistor in the voltage-dividing circuit 505. Similarly, in the solution of this embodiment, the voltage-dividing resistor value is adjustable, which means that the resistance value of each voltage-dividing resistor is adjusted while the voltage-dividing ratio remains unchanged.

[0133] In the above solution, the voltage divider resistance value of the resistor voltage divider circuit 505 is adjustable, which can easily change the power consumption of the first power-on reset circuit 504, that is, change the overall power consumption of the watchdog circuit, and improve the configuration flexibility of the watchdog circuit.

[0134] And / or, in some embodiments, the resistance and capacitance of the resistor-capacitor charging circuit 503 are adjustable.

[0135] The resistance value is the resistance value of the resistor in the resistor-capacitor charging circuit 503, and the capacitance value is the capacitance value of the capacitor in the resistor-capacitor charging circuit 503. In this embodiment, by changing the resistance and capacitance of the resistor-capacitor charging circuit 503, the charging time of the resistor-capacitor charging circuit 503 can be changed, thereby changing the duration of the level signal output by the logic processing circuit 506 during initial power-up, for example, the duration of the low-level signal during initial power-up.

[0136] In the above solution, the resistance and capacitance of the resistor and capacitor charging circuit 503 are adjustable, thereby changing the charging time of the resistor and capacitor charging circuit 503 to meet the operating requirements of different scenarios and improve the configuration flexibility of the watchdog circuit.

[0137] Referring to Figure 5, in some embodiments, the resistor-capacitor charging circuit 503 includes an eighth resistor R8 and a fifth capacitor C5 connected in series. The connection point of the eighth resistor R8 and the fifth capacitor C5 is connected to the first input terminal of the second comparator 501, the end of the eighth resistor R8 away from the fifth capacitor C5 is connected to the power supply, and the end of the fifth capacitor C5 away from the eighth resistor R8 is grounded.

[0138] In this embodiment, an eighth resistor R8 and a fifth capacitor C5 are connected in series to form a resistor-capacitor charging circuit 503. According to the charging formula for an RC charging circuit, by changing the resistance value of the eighth resistor R8 and / or the capacitance value of the fifth capacitor C5, the charging time of the resistor-capacitor charging circuit 503 can be changed, thereby adjusting the level maintenance time when the logic processing circuit 506 is initially powered on.

[0139] In the above solution, the resistor-capacitor charging circuit 503 is constructed by the eighth resistor R8 and the fifth capacitor C5, and is connected to the first input terminal of the second comparator 501 through the common connection point of the two, providing the required voltage for the first input terminal of the second comparator 501. The circuit structure is simple and can effectively save circuit costs.

[0140] And / or, referring to Figure 5, in some embodiments, the resistance divider circuit 505 includes a ninth resistor R9 and a tenth resistor R10 connected in series, the connection point of the ninth resistor R9 and the tenth resistor R10 is connected to the second input terminal of the second comparator 501, the end of the ninth resistor R9 away from the tenth resistor R10 is connected to the power supply, and the end of the tenth resistor R10 away from the ninth resistor R9 is grounded.

[0141] In the solution of this embodiment, a resistor voltage divider circuit 505 is constructed by using a resistor voltage divider, so that after the power supply voltage is divided, a reference voltage is provided to the second input terminal of the second comparator 501 .

[0142] It should be noted that the resistance values ​​of the ninth resistor R9 and the tenth resistor R10 are not unique and can be the same or different, without specific limitation. For example, in some embodiments, the resistance values ​​of the ninth resistor R9 and the tenth resistor R10 can both be set to megaohms, such as 4.7 MΩ (megaohms).

[0143] In the above solution, the resistor divider circuit 505 is constructed by connecting the ninth resistor R9 and the tenth resistor R10 in series, and the common connection point between the ninth resistor R9 and the tenth resistor R10 is connected to the second input terminal of the second comparator 501, thereby providing the required reference voltage for the second input terminal of the second comparator 501. The circuit structure is simple and can effectively save circuit costs.

[0144] In some embodiments, the second comparator 501 comprises a low-power comparator with a quiescent current in the nanoampere range. Similarly, to minimize the power consumption of the watchdog circuit, a comparator with even lower power consumption should be selected as the first comparator 102. In the above solution, the second comparator 501 employs a low-power comparator with a quiescent current in the nanoampere range, which can further reduce the power consumption of the watchdog circuit.

[0145] In some embodiments, the logic processing circuit 506 includes a logic AND circuit.

[0146] The specific type of logic processing circuit 506 is not unique. In the embodiment, the logic processing circuit 506 is a logic AND circuit, which performs the AND operation of the outputs of the second comparator 501 and the first comparator 102. When the power is first turned on, the output of the second comparator 501 is a low-level signal. After ANDing the output of the first comparator 102, the output remains low. After a period of charging, the second comparator 501 outputs a high-level signal, which is logically ANDed with the output of the first comparator 102. The actual output level of the monitored object is determined by the first comparator 102.

[0147] The above solution can use a logic AND circuit as the logic processing circuit 506 to implement the first power-on reset function when the first power-on reset circuit 504 outputs a low-level signal, thereby improving the operational reliability of the watchdog circuit.

[0148] Referring to FIG. 6 , in some embodiments, the logic processing circuit 506 includes a first diode and a second diode. The cathode of the first diode is connected to the output of the first comparator 102 , the cathode of the second diode is connected to the first power-on reset circuit 504 , and the anode of the first diode is connected to the anode of the second diode. The anodes of the first diode and the second diode form a common terminal, which serves as the output of the logic processing circuit 506 .

[0149] The diode type is not limited to a single type; it can be a Schottky diode or other type of diode, without specific limitation. For ease of understanding, the present application embodiments use a Schottky diode as an example for explanation. A Schottky diode is a semiconductor diode with a low forward voltage drop and very fast switching action. The solution of this embodiment utilizes Schottky diodes to implement logic and functions, with the advantages of low cost and low circuit power consumption.

[0150] It should be pointed out that in actual application scenarios, a Schottky diode with a small reverse cutoff leakage current should be selected. For details, refer to Figure 7, which takes a Schottky diode with a reverse leakage current of less than 100nA and a maximum reverse voltage of 50V as an example. In order to reduce the low-level voltage, when the pull-up resistor is large, the voltage drop generated is small. At 25°C (degrees Celsius) in the figure, a 100K (kilo) ohm pull-up resistor generates a 0.03mA (milliampere) current and a voltage drop of about 0.25V, which meets the requirement of resetting the low-level reset voltage.

[0151] The above solution uses two Schottky diodes to construct the logic processing circuit 506 to implement the logic AND function, which can effectively reduce circuit cost and power consumption.

[0152] It should be noted that the specific form of the logic processing circuit is not unique. Please refer to FIG. 5 . In some embodiments, the logic processing circuit can also be directly implemented using an AND gate chip, which is not specifically limited.

[0153] In some embodiments, the logic processing circuit further includes a pull-up resistor and a lower-end capacitor, wherein the first end of the pull-up resistor is connected to the power supply, the second end of the pull-up resistor is connected to the common end, the first end of the lower-end capacitor is connected to the common end, and the second end of the lower-end capacitor is grounded.

[0154] This solution can also provide a pull-up resistor and a lower-end capacitor between the logic operation circuit constructed by the Schottky diode and the object to be monitored. The pull-up resistor and the lower-end capacitor are used in conjunction with the Schottky diode to realize the logic operation function, thereby improving the operating reliability of the logic processing circuit 506.

[0155] It is understandable that in other embodiments, the pull-up resistor and the lower capacitor may be integrated into the object to be monitored, and the configuration may be based on actual needs.

[0156] The above solution further connects a pull-up resistor and a lower-end capacitor between the output of the logic processing circuit 506 and the object to be monitored, thereby improving the operational reliability of the logic processing circuit 506 .

[0157] To facilitate understanding of the technical solution of the present application, please refer to FIG6 . The present application will be explained below in conjunction with a more detailed embodiment.

[0158] For the hysteresis comparator circuit 103: After the power supply VCC is powered on, the positive terminal (first input terminal) of the first comparator 102 is divided to generate a voltage. Compared with the capacity of the second capacitor C2 connected to the negative terminal (second input terminal), it is larger and charges more slowly, which is equivalent to a ground short circuit. The first comparator 102 starts to output a positive voltage, which is a divided voltage. At this time, the positive terminal voltage is the parallel connection of the second resistor R2 and the first resistor R1, and then connected in series with the third resistor R3. The voltage division value is: VCC*R3 / (R1||R2+R3), R1 and R3 are megohm resistors. When the dog feeding circuit 101 has a dog feeding signal, the second capacitor C2 will be discharged all the time, and the positive terminal voltage of the first comparator 102 will continue to be higher than the negative terminal voltage. The high level output of the first comparator 102 will not change.

[0159] When the dog feeding circuit 101 does not receive a dog feeding signal, the first switch Q1 of the dog feeding circuit 101 is turned off, meaning there is no switch discharging the second capacitor C2. The VCC output by the first comparator 102 charges the second capacitor C2 via the fourth resistor R4. After a period of charging, the voltage on the second capacitor C2 exceeds the positive terminal voltage of the first comparator 102, causing the signal to flip and the output of the first comparator 102 to output a low level. At this time, the positive terminal voltage of the first comparator 102 becomes the voltage of the second resistor R2 and the third resistor R3 in parallel, which are then connected in series with the first resistor R1, with a voltage divider value of VCC*(R3||R2) / ((R3||R2)+R1). The output of the first comparator 102 outputs a low level, and the second capacitor C2 discharges via the fourth resistor R4 until the capacitor voltage drops below the positive terminal voltage of the first comparator, causing the output of the first comparator 102 to flip again. The first comparator 102 compares two different voltages to generate a holding time of the output level, and the holding time is determined by the RC charging and discharging time of the fourth resistor R4 and the second capacitor C2.

[0160] Dog feeding circuit 101: The sixth resistor R6 and the fourth capacitor C4 are connected in series to form an AC coupling circuit 401. On the rising edge of the pulse signal, the fourth capacitor C4 and the charging device C3 are charged, causing the voltage of the charging device C3 to increase. The first switching device Q1 (NMOS transistor) is controlled to conduct, discharging the second capacitor C2 to ground. The fifth resistor R5 is a pull-down resistor, reducing the possibility of interference and abnormalities in the NMOS transistor. On the falling edge of the pulse voltage, the charging device C3 discharges externally, providing a discharge path for the unidirectional conductive switch D1, reducing the possibility of negative voltage on the NMOS transistor.

[0161] Initial power-on reset circuit 504: The ninth resistor R9 and the tenth resistor R10 divide a reference voltage and input it to the inverting input of the second comparator 501. The eighth resistor R8 and the fifth capacitor C5 form a delayed charging circuit, the middle position of which is input to the non-inverting input of the second comparator 501. During initial power-on, a low-level signal is output through the second comparator 501. The duration of the low-level signal is determined by the RC charging time of the eighth resistor R8 and the fifth capacitor C5. The desired low-level duration during initial power-on can be selected by adjusting the values ​​of the eighth resistor R8 and the fifth capacitor C5. After a period of charging, the voltage at the positive terminal of the second comparator 501 is greater than the voltage at the negative terminal, and the second comparator 501 changes to outputting a high-level signal.

[0162] Enable circuit 502: Utilizes a low-power MOS transistor design. A high level is used to disable the watchdog function in the diagram. If inverse logic control is required, a MOS transistor can be added for inversion. When the monitored object outputs a high level, the second switch Q2 turns on, dropping the capacitor voltage of the second capacitor C2 to ground. This causes the voltage at the inverting input of the first comparator 102 to approach 0V, causing the first comparator 102 to continuously output a high level and prevent the reset low-level signal from being triggered. In practical scenarios, the monitored object's power-on port outputs a low level. To prevent a system reset, an inverting circuit, such as an inverter or an NMOS transistor, can be added for inverting logic.

[0163] Logic processing circuit 506: It is necessary to perform a logical AND operation on the outputs of the first comparator 102 and the second comparator 501 to ensure that when one of the outputs is low, the RST (reset signal) output to the monitored object is also low. This can be achieved using an AND gate or a Schottky diode. The functions of the hysteresis comparator circuit 103 and the first power-on reset circuit 504 can be combined to maintain the output low-level signal when first powered on. As the fifth capacitor C5 in the first power-on reset circuit 504 charges, the second comparator 501 outputs a high-level signal, which is then logically ANDed with the output of the first comparator 102.

[0164] The present application also provides an electronic power device, including a controller and the above-mentioned watchdog circuit.

[0165] The watchdog circuit is shown in the above embodiments and the accompanying drawings, and will not be described in detail here. The electronic power device uses a voltage divider circuit 202, a charge and discharge circuit 204, and a first comparator 102 to form a hysteresis comparison circuit 103. The first input of the first comparator 102 is connected to the output of the first comparator 102 through the voltage divider circuit 202, and the second input of the first comparator 102 is connected to the output of the first comparator 102 through the charge and discharge circuit 204. The dog feeding circuit 101 is connected to the charge and discharge circuit 204. During actual operation, the reference voltage can be input to the first input of the first comparator 102 through the voltage divider circuit 202. The dog feeding circuit 101 adjusts the charge and discharge state of the charge and discharge circuit 204 on the second input of the first comparator 102 according to whether the dog feeding signal is received, thereby changing the input voltage of the second input of the first comparator 102. Finally, based on the comparison and analysis of the reference voltage and the input voltage, the output of the first comparator 102 feeds back a corresponding level signal to realize monitoring and restart control of the object to be monitored connected thereto. The watchdog circuit constructed in this application has circuit parameters that can be flexibly adjusted according to actual needs. While combining the operating status of the dog feeding circuit 101 to realize the monitoring and restart control functions, it can also have low power consumption and can meet the low-power operation requirements of devices with higher power consumption requirements.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A watchdog circuit, comprising a dog feeding circuit and a hysteresis comparison circuit, wherein the hysteresis comparison circuit comprises a voltage divider circuit, a charge and discharge circuit and a first comparator; The first input end of the first comparator is connected to the output end of the first comparator through the voltage divider circuit, the second input end of the first comparator is connected to the output end of the first comparator through the charge and discharge circuit, and the dog feeding circuit is connected to the charge and discharge circuit.

2. The watchdog circuit according to claim 1, wherein: The voltage divider circuit includes a resistor voltage divider unit and a delay unit. The resistor voltage divider unit is connected to the output terminal and the power supply of the first comparator respectively. The resistor voltage divider unit is also connected to the delay unit. The delay unit is connected to the first input terminal of the first comparator.

3. The watchdog circuit according to claim 2, wherein: The resistor divider unit includes a first resistor and a second resistor, wherein the first end of the first resistor is connected to a power supply, the second end of the first resistor is connected to the first end of the second resistor and the delay unit, and the second end of the second resistor is connected to the output end of the first comparator.

4. The watchdog circuit according to claim 2 or 3, wherein: The delay unit includes a third resistor and a first capacitor, the first end of the third resistor is connected to the first end of the first capacitor and the first input end of the first comparator, the first end of the first capacitor is also connected to the resistor divider unit, and the second end of the first capacitor and the second end of the third resistor are grounded.

5. The watchdog circuit according to any one of claims 1 to 4, wherein: The charge and discharge circuit includes a fourth resistor and a second capacitor, wherein a first end of the fourth resistor is connected to an output end of the first comparator, a second end of the fourth resistor is connected to a first end of the second capacitor and a second input end of the first comparator, a first end of the second capacitor is also connected to the dog feeding circuit, and a second end of the second capacitor is grounded.

6. The watchdog circuit according to any one of claims 1 to 5, wherein: The dog feeding circuit includes an AC coupling circuit, a charging device and a first switching device. The input end of the AC coupling circuit is used to receive a dog feeding signal. The output end of the AC coupling circuit is connected to the first end of the charging device and the control end of the first switching device. The input end of the first switching device is connected to the charge and discharge circuit. The second end of the charging device and the output end of the first switching device are grounded.

7. The watchdog circuit according to any one of claims 1 to 6, wherein: The watchdog circuit further includes an enabling circuit, and the enabling circuit is connected to the charging and discharging circuit.

8. The watchdog circuit according to claim 7, wherein: The enabling circuit includes a seventh resistor and a second switch device, wherein a first end of the seventh resistor is connected to a control end of the second switch device, the control end of the second switch device is used to input an enabling signal, an output end of the second switch device is connected to the voltage divider circuit, and a second end of the seventh resistor and an output end of the second switch device are grounded.

9. The watchdog circuit according to claim 8, wherein: The enabling circuit further includes an inverting circuit, the control end of the second switch device is connected to the output end of the inverting circuit, and the input end of the inverting circuit is used to input an enabling signal.

10. The watchdog circuit according to any one of claims 1 to 9, wherein: The watchdog circuit also includes a first power-on reset circuit and a logic processing circuit, the output end of the first comparator is connected to the first input end of the logic processing circuit, the first power-on reset circuit is connected to the second input end of the logic processing circuit, and the output end of the logic processing circuit is used to output a logic processing signal.

11. The watchdog circuit according to claim 10, wherein: The first power-on reset circuit includes a resistor voltage divider circuit, a resistor-capacitor charging circuit and a second comparator, the resistor-capacitor charging circuit is connected to the first input end of the second comparator, the resistor voltage divider circuit is connected to the second input end of the second comparator, and the output end of the second comparator is connected to the second input end of the logic processing circuit.

12. The watchdog circuit according to claim 11, wherein: The resistor-capacitor charging circuit includes an eighth resistor and a fifth capacitor connected in series, wherein the connection point between the eighth resistor and the fifth capacitor is connected to the first input terminal of the second comparator, an end of the eighth resistor away from the fifth capacitor is connected to the power supply, and an end of the fifth capacitor away from the eighth resistor is grounded.

13. The watchdog circuit according to claim 11 or 12, wherein: The resistance divider circuit includes a ninth resistor and a tenth resistor connected in series, wherein the connection point between the ninth resistor and the tenth resistor is connected to the second input terminal of the second comparator, an end of the ninth resistor away from the tenth resistor is connected to the power supply, and an end of the tenth resistor away from the ninth resistor is grounded.

14. The watchdog circuit according to any one of claims 10 to 13, wherein: The logic processing circuit includes a first diode and a second diode, the cathode of the first diode is connected to the output end of the first comparator, the cathode of the second diode is connected to the first power-on reset circuit, the anode of the first diode is connected to the anode of the second diode, and the common end formed by the anode of the first diode and the anode of the second diode serves as the output end of the logic processing circuit.

15. The watchdog circuit according to claim 14, wherein: The logic processing circuit also includes a pull-up resistor and a lower capacitor, wherein the first end of the pull-up resistor is connected to a power supply, the second end of the pull-up resistor is connected to the common end, the first end of the lower capacitor is connected to the common end, and the second end of the lower capacitor is grounded.

16. An electronic power device, comprising a controller and the watchdog circuit according to any one of claims 1 to 15.

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